I have the Surgical Seam Ripper (2 of them in fact) from Nancy's Notion's. They're super sharp and I haven't poked a hole in fabric since I got them! I use one for my hand embroidery and the other stays on my sewing machine.
Tried to post a link but it doesn't work. I'm new - haven't got the hang of that yet! You can find it in her on-line catalog.